Donepezil hydrochloride (Aricept - Eisai), a piperidine-based acetylcholinesterase inhibitor, is now being marketed for oral treatment of cognitive symptoms in patients with mild to moderate dementia due to Alzheimer's disease. Donepezil is the second drug approved for this indication; tacrine hydrochloride (Cognex), also an acetylcholinesterase inhibitor, has been available in the USA for four years (Medical Letter, 35:87, 1993).

A once-weekly transdermal formulation of the acetylcholinesterase inhibitor donepezil (Adlarity – Corium) has been approved by the FDA for treatment of mild, moderate, and severe Alzheimer's disease (AD) dementia. Donepezil is the second acetylcholinesterase inhibitor to become available in a transdermal formulation; transdermal rivastigmine (Exelon Patch), which is applied once daily, has been available for years for the same indication. Donepezil is also available in oral formulations (Aricept, and generics) for treatment of AD dementia.

The FDA has approved Namzaric (Forest), a fixed-dose combination of extended-release (ER) memantine (Namenda XR), an NMDA-receptor antagonist, and donepezil (Aricept, and generics), an acetylcholinesterase inhibitor, for treatment of moderate to severe Alzheimer's type dementia in patients previously stabilized on both drugs. The patent for Namenda has recently expired and generic formulations of memantine 5- and 10-mg tablets have been approved.

Alzheimer's disease (AD) is the most common cause of dementia, but cognitive decline is also associated with other neurological conditions such as Parkinson's disease, dementia with Lewy bodies, vascular dementia, and frontotemporal dementia.

Rivastigmine tartrate (Exelon - Novartis), a carbamate-based cholinesterase inhibitor, is now being marketed for treatment of patients with dementia due to Alzheimer's disease.

View the Comparison Table: Drugs for Alzheimer's Disease

Galantamine hydrobromide (Reminyl), a tertiary alkaloid and phenanthrene derivative extracted from daffodil bulbs, is now being marketed for oral treatment of mild to moderate Alzheimer's disease. Galantamine is the fourth acetylcholinesterase inhibitor approved for this indication.

View Table: Mechanisms of Drug Interactions

Memantine hydrochloride, which has been used to treat dementia in Germany (Axura Merz) since 1982, has become the latest word-of-mouth miracle drug for Alzheimer's disease in the US (G Kolata, NY Times, June 15, 2003). Forest Laboratories has submitted a New Drug Application to the FDA for memantine. This review describes the standard treatment for Alzheimer's Disease, mechanism of action, clinical studies, adverse effects and dosage. Also included are sections on availability of the drug and how some people are obtaining memantine from abroad.

Aducanumab-avwa (Aduhelm – Biogen/Eisai), an IV amyloid beta-directed monoclonal antibody, has received accelerated approval from the FDA for treatment of Alzheimer's disease. The approval was based on the surrogate endpoint of reduction in amyloid beta plaques in the brain. The manufacturer is required to conduct an additional randomized controlled trial to establish that reducing amyloid beta plaques with aducanumab improves clinical outcomes in patients with Alzheimer's disease.